Exciton-polariton state in nanocrystalline SiC films |
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| Institution: | 1. ICQD, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, Anhui, China;2. School of Physics, The University of New South Wales, Sydney 2052, Australia;1. Department of Physics, University of Pretoria, Pretoria 0002, South Africa;2. College of Graduate Studies, University of South Africa, UNISA 0003 Pretoria, South Africa;3. National Institute for Theoretical Physics, Johannesburg 2000, South Africa;1. Department of Mathematics, Faculty of Science, King Abdulaziz University, Jeddah 21589, Saudi Arabia;2. Department of Mathematics, Faculty of Science, Kafrelsheikh University, Kafrelsheikh 33516, Egypt;1. Department of Theoretical Physics, V. Lashkaryov Institute of Semiconductor Physics, NASU, Pr. Nauki 41, Kiev 03028, Ukraine;2. Department of Electrical and Computer Engineering, North Carolina State University, Raleigh, NC 27695-7911, USA |
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| Abstract: | We studied the features of optical absorption in the films of nanocrystalline SiC (nc-SiC) obtained on the sapphire substrates by the method of direct ion deposition. The optical absorption spectra of the films with a thickness less than ~500 nm contain a maximum which position and intensity depend on the structure and thickness of the nc-SiC films. The most intense peak at 2.36 eV is observed in the nc-SiC film with predominant 3C-SiC polytype structure and a thickness of 392 nm. Proposed is a resonance absorption model based on excitation of exciton polaritons in a microcavity. In the latter, under the conditions of resonance, there occurs strong interaction between photon modes of light with λph=521 nm and exciton of the 3С polytype with an excitation energy of 2.36 eV that results in the formation of polariton. A mismatch of the frequencies of photon modes of the cavity and exciton explains the dependence of the maximum of the optical absorption on the film thickness. |
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| Keywords: | Nanocrystalline SiC films SiC polytype Resonance absorption Microcavity Exciton polariton |
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